"the outline of a figure," 1660s, a term in painting and sculpture, from French contour "circumference, outline," from Italian and Medieval Latin contornare "to go around," from assimilated form of Latin com-, here probably an intensive prefix (see com-), + tornare "to turn (on a lathe);" see turn (v.).
Application to topography is from 1769. Earlier the word was used to mean "bedspread, quilt" (early 15c.) in reference to its falling over the sides of the mattress. Contour line in geography is from 1844. Contour-chair, one designed to fit the curves of the body, is from 1949.
As a verb, "mark with contour lines; form to the contours of," 1871. Related: Contoured.